Machines such as dozers, loaders, excavators, motor graders, and other types of heavy machinery use one or more hydraulic actuators to accomplish a variety of tasks. These actuators are fluidly connected to a pump on the machine that provides pressurized fluid to chambers within the actuators. Valve arrangements are fluidly connected between the pump and the actuators to control a flow rate and direction of pressurized fluid to and from the chambers of the actuators. Valve arrangements may also be fluidly connected between the actuator and the tank to control the back pressure of fluid exiting the actuator.
One valve arrangement for controlling back pressure is disclosed in U.S. Pat. No. 7,302,797 to Jiao Zhang, et al (the “797 patent”). However, it may be beneficial to provide a valve arrangement for controlling back pressure that allows the back pressure to be selectively controlled.